Transcript Joints and Movement dl

Joints and Movement
Articulations = Joints
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Functional junctions between bones
Bind parts of the skeletal system
Make bone growth possible
Permit skeletal change during childbirth
Enable movement in response to muscle
contraction
• Skeleton Review Video
3 Types of Cartilage
Classification of Joints
• Classification based
on the type of tissue
that binds the bones:
• Fibrous joints
• Cartilaginous joints
• Synovial joints
• Classification
according to degree of
movement possible:
• Immovable
(synarthrotic)
• Slightly movable
(amphiarthrotic)
• Freely movable
(diarthrotic)
Fibrous Joints (Synarthrotic)
• Dense CT with many
collagenous fibers
• Lie between bones that are
in close contact
• Suture – only between flat
bones of the skull
• Gomphosis – joint between
tooth and socket; periodontal
ligament
Fibrous Joints
Cartilaginous Joints
(Amphiarthrotic)
• Consist of hyaline or
fibrocartilage
• 2 types:
• Synchondrosis – bands
of hyaline cartilage
• Epiphyseal plate
• Costal cartilage
• Symphysis – pad of
fibrocartilage that allows
limited movement
• Intervertebral disks
• Symphysis pubis
• Slightly movable
(amphiarthrotic)
Cartilaginous Joints
(amphiarthrotic)
Synovial Joints (Diarthrotic)
• Articular cartilage
(hyaline cartilage) covers
the ends of bones
• A fibrous articular
capsule encloses joint
surfaces
• A joint cavity is filled
with synovial fluid
• Ligaments reinforce the
joint
• Most joints in the body
are synovial
Synovial Joint Structure
(Diarthrotic)
• Articular cartilage –
hyaline cartilage; resists
wear and minimizes friction
• Subchondral plate –
somewhat elastic bone
located under the articular
cartilage
• Absorbs shocks and
helps protect joint from
stresses
• May fracture from
excessive stress from
obesity or athletic
activities
Synovial Joint Structure continued…
• Joint capsule – has 2 distinct
layers:
• Outer layer consists of dense CT
whose fibers attach to the
periosteum
• Flexible enough to allow
movement but strong enough to
hold the joint together
• Ligaments – bundles of strong,
tough cartilaginous fibers that
reinforce the joint capsule
• Synovial membrane – inner
layer of the joint capsule
• Shiny, vascular lining of loose
CT only a few cells thick
• Covers all surfaces within the
the joint capsule except the
articular cartilage
Synovial Joint Structure continued…
• Synovial cavity – area
enclosed by the joint
capsule
• Synovial fluid – clear
fluid secreted by the
synovial membrane that
moistens and lubricates
the joint cavity and
supplies nutrients to the
cartilage
Synovial Joint Structure continued…
• Menisci – fibrocartilage
disks that partially or
completely divide the joint
into compartments between
the articular surfaces
• Bursae – flattened fibrous
sacs lined with synovial
membrane and containing a
thin film of synovial fluid.
Common where ligaments,
muscles, skin, tendons, or
bones rub together.
• Knee Replacement Surgery
Ball-and-Socket Joints
• Bone with a globular
head articulates with
the cup-shaped cavity
of another bone
• Widest range of
motion and rotation
• Examples – hip,
shoulder
Condyloid Joints
• Ovoid condyle fits
elliptical cavity
• Wide range of motion,
but no rotation
• Examples – metacarpals
and phalanges
Gliding (plane) Joints
• Nearly flat or slightly
curved articulating surfaces
• Allow sliding (back and
forth) and twisting
movements
• Examples – within the wrist
and ankle, between
vertebrae, sacroiliac joint,
between ribs and sternum
Hinge Joints
• Convex surface of one
bone joins concave
surface of another bone
• Movement in one plane
only
• Examples – elbow,
phalanges
Pivot Joints
• Cylindrical surface of
one bone rotates within
a ring of bone
• Allows rotation only
• Examples – proximal
radius and ulna, atlas
and axis
Saddle Joints
• Bones with concave and
convex regions on
articulating surfaces
• Allows movement in 2
planes
• Example – trapezium
and metacarpal 1
(thumb)
Joints Review
(8:11)
Types of Ordinary Body
Movements
• Flexion
• Decreases the angle of the
joint
• Brings two bones closer
together
• Typical of hinge joints like
knee and elbow
• Extension
• Opposite of flexion
• Increases angle between
two bones
Types of Ordinary Body
Movements
• Rotation
• Movement of a bone
around its longitudinal
axis
• Common in ball-andsocket joints
• Example is when you
move atlas around the
dens of axis (shake your
head “no”)
Types of Ordinary Body
Movements
• Abduction
• Movement of a limb
away from the
midline
• Adduction
• Opposite of
abduction
• Movement of a limb
toward the midline
Types of Ordinary Body
Movements
• Circumduction
• Combination of
flexion, extension,
abduction, and
adduction
• Common in ball-andsocket joints
Special Movements
• Dorsiflexion
• Lifting the foot so that
the superior surface
approaches the shin
• Plantar flexion
• Depressing the foot
(pointing the toes)
Special Movements
• Inversion
• Turn sole of foot
medially
• Eversion
• Turn sole of foot
laterally
Special Movements
• Supination
• Forearm rotates laterally so palm faces
anteriorly
• Pronation
• Forearm rotates medially so palm faces
posteriorly
Special Movements
• Opposition
• Move thumb to touch the tips of other fingers
on the same hand
Joint Movements
• Protraction
• moving a part forward
• Retraction
• moving a part
backward
• Elevation
• raising a part, shrug
the shoulder
• Depression
• lowering a part, droop
the shoulder
Shoulder Joint
• Ball and socket joint made up of the
rounded head of the humerus and the
glenoid cavity of the scapula.
• The joint capsule is loose. Muscles and
tendons reinforce the joint.
• Shoulder joint is capable of a wide range of
movements including flexion, extension,
abduction, adduction, rotation, and
circumduction.
Shoulder Joint
• Ligaments: coracohumeral ligament,
glenohumeral ligaments, transverse humeral
ligament, and glenoid labrum
• Bursae: subscapular, subdeltoid,
subacromial, subcorocoid bursae
Coracoacromial
Ligament
Coracoclavicular Ligament
Knee Joint
• The knee is the largest and
most complex synovial joint.
• It consists of the medial and
lateral condyles at the
proximal end of the tibia.
The femur articulates with
the patella.
• The joint capsule is thin and
strengthened by muscles and
tendons.
Knee Joint
• Ligaments of the knee joint: patella, oblique
popliteal, arcuate popliteal, tibial collateral
(MCL), fibular collateral ligament (LCL),
anterior cruciate ligament (ACL) strengthen
the joint capsule.
• Cruciate ligaments prevent displacement of
articulating surfaces.
• Two fibrocartilaginous menisci separate the
articulating surfaces.
Life-Span Changes
• Joint stiffness
occurs due to a
change in
collagen
structure.
• Fibrous joints
strengthen over a
lifetime.
Life-Span Changes
• Synchondrosis
disappear over time
as part of skeletal
growth and
development.
• Symphysis joints
may lose water and
flexibility may
decrease.